For as long as humans have piloted watercraft over bodies of water, humans have attempted to improve the design of their watercraft hulls. Historically, watercraft hulls have been in three well known classes: flat-bottomed planing hulls, deep vee hulls, and tunnel hulls. Each class of historical hull has associated with its shape certain advantages and certain disadvantages. Flat-bottomed planing hulls encounter minimal resistance with the water surface, but can be directionally unstable. Deep vee hulls can be directionally stable, but have increased water friction. Tunnel hulls can also be directionally stable, but may have a tendency to have an excessive angle of inclination and can be susceptible to tail or head winds. None of these historical watercraft hull shapes provides minimal water resistance together with directional stability and an acceptable angle of inclination not susceptible to tail or head winds.
There are several watercraft hull shapes that have attempted to solve this problem. For example, U.S. Pat. No. 3,363,598 to Mortrude, discloses a watercraft hull shape for minimizing frictional resistance, maximizing ride quality and increasing directional stability. The design includes a deep vee hull shape with a flat delta-shaped planing surface along the keel line. The delta-shaped planing surface is situated so that the apex thereof is oriented toward the bow and increases in width as it approaches the stern.
U.S. Pat. No. 4,022,143 to Krenzler discloses a watercraft hull shape which combines hydrodynamic efficiency and seaworthiness. The design includes a transom stern, freeboard side portions and a wide-keeled lower hull portion which comprises keel sidewalls forming steep, relatively constant deadrise angles and keel bottom surfaces which are flat at the transom and progress forwardly to form shallow deadrise angles. First steps having shallow deadrise angles are located adjacent the keel sidewalls, second steps having similar deadrise angles are located adjacent the side portions, and risers having steep deadrise angles interconnect the first and second steps.
U.S. Pat. No. 4,091,761 to Fehn discloses a watercraft hull shape that minimizes the tendency of the attitude of a tunnel hull boat to be affected by head or tail winds and avoids undue raising of the bow of a tunnel hull boat at high speeds. The hull contains a tunnel between the inner walls of two downwardly extending sponsons, and a center rib projecting downwardly from the bottom of the boat into the tunnel, the lower wall of which acts as a planing surface. The distance between the inner walls of the sponsons and the outer walls of the center rib decreases from the bow to an area adjacent the midpoint of the boat fore and aft and then increases abruptly after this point so as to create a venturi throat. Two flat portions adjacent the bow, which are directed upwardly in a forward direction, act as scoops to increase the lifting effect on the stern. Curved strakes of short length adjacent the bow give additional lift to the bow at low speeds.
U.S. Pat. No. Re. 36,879 to Schoell discloses a watercraft hull shape that increases lateral stability at non-planing speeds, that has lateral stability at low and planing speeds, and whose spray is directed away from occupants of the boat. The hull has a conical contour extending from the bow portion to a stern portion having a flat surface on each side of the keel, a wide lip chine having a lip portion and a transom separating the bow portion and the stern portion creating a step between the bow portion and the stern portion. A flat keel portion extends from the stern to the mid hull transom.
U.S. Pat. No. 6,631,690 to Mambretti discloses a watercraft hull shape that increases lift in relation to speed, greatly improves performance, strengthens the structure of the boat and that reacts to the lateral thrust from the water-air mixture tending to move from the keel outwards to the sides of the bottom. The deep vee hull has a number of longitudinal grooves substantially parallel and symmetrical to the keel extending from the stern approximately as far as the bow. The hull may have two, four or some other number of grooves which may be of different lengths or may appear different in cross section.
U.S. Published Patent Application No. 2009/0188419 to Lindstrom et al. discloses a watercraft hull shape having aerated longitudinal hydrosponsons with air injection into tunnels and distribution to generate bubbles across central running surfaces. The Lindstrom '419 patent application contemplates distributing air across the center hull surfaces and enhancing air flow into tunnel hull configurations outboard of the center V-hull zones. The Lindstrom '419 patent application specifically discloses a deep V-hull that extends substantially from the bow of the watercraft to the stern of the watercraft. Further, air injection into the tunnels is accomplished using air induction shields which merely permit flow of air into the tunnels through conduits.
There exists a need to provide a watercraft hull having a shape and structure that provides minimal water resistance, resulting in higher performance and improved fuel economy, together with directional stability and an acceptable angle of inclination not unreasonably susceptible to tail or head winds.